66 SCIENTIFIC SURVEY OF NORWICH AND DISTRICT 
when the Wretham meres were drained, and also at Barton Mere, whilst 
possible hut circles have been noted at Litcham, Wellingham and 
Weasenham, but these await excavation. The hollows on the Cromer- 
Holt ridge appear to be of later date. 
FLInt MINEs. 
It is now generally accepted that the flint mining characterises the 
Late Neolithic and Early Bronze Ages, being practically abandoned by the 
Early Iron Age, but Armstrong’s claim for an earlier beginning at Grime’s 
Graves requires consideration. Here mining was certainly carried out 
on a comparatively enormous scale, suggesting either a prolonged duration, 
or, less probably, a comparatively short spell of intense productivity. 
Of the 34 acres, 164 are occupied by nearly 400 saucer-shaped hollows, 
from 12-70 ft. in diameter, each indicating a filled-in shaft. Over the 
remaining 174 acres no surface indications are visible, but excavations show 
that the area is closely crowded with mine shafts of small diameter. 
Recently, fresh shafts have been exposed at Lyndford. Armstrong ?9 
has stated the problem of Grime’s Graves under six heads : 
(1) The presence in the pits and on the chipping floors of numerous 
artifacts of Paleolithic type. 
(2) That these artifacts have been manufactured on the site and in the 
traditional Palzolithic technique. 
(3) The presence of Levallois flakes and tortoise cores. 
(4) That these artifacts have been found associated with an advanced 
method of mining, in which polished axes appear to have been 
used. 
(5) That celt-like forms occur on some chipping floors, but no polished 
implements have been found. 
(6) That the fauna, though including Pleistocene animals, includes 
none which are exclusively Pleistocene, red deer and short-horn ox 
predominating. 
It has been the aim of the post-war work to elucidate these points. 
The pits previously excavated had been sunk to a depth of 30 ft. 
through successive layers of sand, boulder clay, chalk, flint (top stone), 
chalk, flint (upper crust), chalk, flint (wall stone), and chalk, to the level 
of the ‘ floor stone,’ the wonderful flaking quality of which rendered it 
so desirable a raw material. Armstrong found that contortions due to 
glacial action had caused outcrops of the floor stone, making it possible 
to obtain it by shallow open workings. This discovery led to the finding 
in 1923 of the group of ‘ primitive pits.’ °° ‘These pits and the tools 
used in sinking them are of a type not previously recorded and undoubtedly 
mark an early phase in the evolution of mining. They are bell-shaped 
at the base, entirely devoid of galleries, and entered by wide steps cut 
in the chalk walls. The picks used were not the familiar deer antler 
picks, but merely long bones of animals, artificially hollowed at the distal 
28 P.P.S.E.A., N, i, pp- 91-127. 30 -P.P.S.B.A., 1Ve ig pe args 
